Oral compositions

ABSTRACT

Oral compositions containing an acrylic acid polymer or copolymer, a soluble fluoride ion source and a strontium ion source are described herein.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of our copending application havingSerial No. 828,120, filed February 10, 1986, now abandoned.

TECHNICAL FIELD

The present invention relates to oral compositions which provide moreefficient fluoride uptake by the enamel of human teeth.

BACKGROUND OF THE INVENTION

The role of fluoride in the remineralization of carious lesions is wellknow. The use of agents to enhance this benefit is also well known. Onesuch agent is strontium.

While strontium's inclusion in oral compositions containing fluoride isdesirable, the agents form an insoluble precipitate unless separatedbefore use or the strontium ions are complexed so as not to be availableto form the precipitate. Strontium EDTA is such a complex.

The effect of strontium-EDTA complex in combination with sodiumrecinoleate and a fluoride source is found in the Journal of DentalResearch (1982) 61 (3) 451-455. The combined effect of strontium andfluoride in reducing the acid solubility of enamel is also disclosed inthe Journal of Dental Research (1983) 62 (10) 1049-1053. A furtherreference discussing the effect of strontium and fluoride Featherstone,J.D.B., "Remineralization of Artificial Carious Lesions In-vivo andIn-vitro", Proceedings of Workshop, (1983) IRL Press Ltd.

The use of strontium in combination with fluoride in oral compositionsis also disclosed in a number of patent references. Included among thesereferences are U.S. Pat. No. 3,888,976, June 10, 1975 to Mlkvysdisclosing an effervescent mouthwash tablet containing strontium ionsand possibly a fluoride ion source. U.S. Pat. No. 4,367,219, Jan. 4,1983 to Schole discloses dentifrices containing a combination ofstrontium EDTA, a recinoleate salt and a fluoride ion source. U.S. Pat.No. 4,415,549, Nov. 15, 1983 to Shah et al. discloses toothpastescontaining a glycyrrhizinate salt, strontium EDTA and a fluoride ionsource. Finally European Patent Application No. 0,079,611, June 6, 1983,Shah, discloses oral compositions containing a strontium EDTA complexand a fluoride ion source.

The use of other materials in oral compositions to provide a variety ofbenefits in combination with soluble fluoride ion sources has also beendisclosed in the patent literature.

Included are certain polymers and other agents. Specific agentsdisclosed are polyelectrolytes such as copolymers of maleic anhydrideand ethylene disclosed in U.S. Pat. No. 3,429,963, Feb. 25, 1969 toShedlovsky. Shedlovsky also discloses polyacrylic acid having an averagemolecular weight of 1500 and greater. Other references disclosingpolyacrylic acids in oral compositions are South African Patent No.720898, Sept. 12, 1972 which discloses such acids having a molecularweight of from 1000 to 1,000,000; and U.S. Pat. No. 4,304,766, Dec. 8,1971 to Chang discloses polyacrylic acid having a molecular weight inthe range of 2,000 to 4,000,000 for use as a membrane to prevent theelution from teeth of previously applied agents. Finally, U.S. Pat. No.3,956,480, to Gaffar, May 11, 1976 discloses complexes of anionicpolymers (e.g., acrylic acid) and a cationic therapeutic agent (e.g.,chlorhexidine) as anticalculus agents.

In spite of the many disclosures of strontium, fluoride ions andpolyacrylic acids in the prior art, there is lacking a suggestion tocombine these agents in a single oral composition. Strontium ions form acomplex with the polyacrylic acid thereby not being able to form aprecipitate with fluoride.

It is therefore an object of the present invention to provide oralcompositions which combine a polyacrylic acid polymer or copolymer,strontium and fluoride.

It is a further object of the present invention to provide a moreeffective anti-caries composition.

It is still a further object of the present invention to provide a moreeffective method of applying fluoride to tooth enamel and dentin.

These and other objects will become more clear from the detaileddescription which follows.

All percentages and ratios used herein are by weight unless otherwisespecified.

SUMMARY OF THE INVENTION

The present invention embraces oral compositions comprising:

(a) a safe and effective amount of a polyacrylic acid polymer orcopolymer;

(b) a safe and effective amount of a strontium ion source;

(c) a safe and effective amount of a fluoride ion source; and

(d) a pharmaceutically acceptable carrier.

The present invention also encompasses a method for retarding thedevelopment of dental caries.

DETAILED DESCRIPTION OF THE INVENTION

The compositions of the present invention comprise polyacrylic acidpolymers or copolymers, a strontium ion source, a fluoride ion sourceand a pharmaceutically acceptable carrier.

By "oral compositions" as used herein means a product which in theordinary course of usage is not intentionally swallowed for purposes ofsystemic administration of particular therapeutic agents, but is ratherretained in the oral cavity for a time sufficient to contactsubstantially all of the dental surfaces and/or oral tissues forpurposes of oral activity.

By "safe and effective amount" as used herein means sufficient amount ofmaterial to provide the desired benefit while being safe to the hard andsoft tissues of the oral cavity.

By the term "comprising", as used herein, is meant that variousadditional components can be conjointly employed in the compositions ofthis invention as long as the listed materials perform their intendedfunctions.

By the term "carrier", as used herein, is meant a suitable vehicle whichis pharmaceutically acceptable and can be used to apply the presentcompositions in the oral cavity.

POLYACRYLIC ACID

The polyacrylic acid polymers are staple items of commerce and are madeby polymerizing acrylic acid, ##STR1## to form the repeating chain##STR2## wherein M is an alkali metal ammonium or hydrogen ion. Polymersof the type useful in the present invention are available from Rohm andHaas Company.

Copolymers of acrylic acid and other monomers may also be used in thepresent invention. Suitable other monomers include methacrylic acid,2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxy propylacrylate and acrylamide. It is preferred that with methacrylic acid, thenumber of acrylic acid units in the polymer be at least 50% of the totalunits present. With other monomers it is preferred that the percentagebe at least 80%. Mixtures of other monomers may also be used.

The molecular weight of the polymer may be in the range of about 1000 toabout 1,200,000 (mass average), preferably the molecular weight is fromabout 4000 to about 10,000, most preferably from about 4300 to about5200. A particularly preferred material is a polyacrylic acid polymerhaving a molecular weight of about 4500 which can be provided by Rohmand Haas carrying the identification LMW-45.

The amount of the polymer used in the present compositions is generallyfrom about 0.0003% to about 13%, preferably from about 0.3% to about5.0%, most preferably from about 0.03% to about 4%. For a dentifricecomposition containing about 220 ppm Sr⁺⁺ the preferred level of polymeris from about 0.3% to about 0.5%. For a mouthwash composition containingabout 225 ppm Sr⁺⁺ the preferred polymer level is from about 0.03% toabout 0.10%. Mixtures of polyacrylic acid polymers or copolymers arealso useful in the present invention.

STRONTIUM ION SOURCE

The strontium ions of the present compositions can be provided by any ofa wide variety of strontium salts or complexes. Included are strontiumchloride, strontium acetate, strontium bromide, strontium glyconate,strontium lactate, strontium hydroxide and strontium salicylate. Inanother execution strontium can be provided to the present compositionsas a complex with the polyacrylic acid. The strontium ion source issoluble enough in the composition at 25° C. or when used to provide fromabout 2 to about 10,000, preferably from about 25 to about 4400 ppmSr⁺⁺.

FLUORIDE ION SOURCE

The water-soluble fluoride compound is present in the compositions ofthis invention in an amount sufficient to give a fluoride concentrationof from about 0.0025% to about 5.0% by weight, preferably from about0.005% to about 2.0% by weight at 25° C., in the composition or whenused to provide anticaries effectiveness. Preferred fluorides are sodiumfluoride, stannous fluoride, indium fluoride, acidulated phosphatefluoride and sodium monofluorophosphate. U.S. Pat. No. 2,946,735, July26, 1960 to Norris et al. and U.S. Pat. No. 3,678,154, July 18, 1972 toWidder et al. disclose such salts as well as others. These referencesare incorporated herein by reference.

PHARMACEUTICALLY ACCEPTABLE CARRIER

The carrier for the components of the present invention can be anyvehicle suitable for use in the oral cavity. Such carriers include theusual components of mouthwashes, toothpastes, topical dental gels,toothpowders, prophylaxis pastes, lozenges, gums and the like and aremore fully described hereinafter. Dentifrices and mouthwashes are thepreferred systems with toothpastes being the more preferred.

Toothpastes contain as a major component an abrasive. The abrasivepolishing material contemplated for use in the present invention can beany material which does not excessively abrade dentin. These include,for example, silicas including gels and precipitates, calcium carbonate,dicalcium orthophosphate dihydrate, calcium pyrophosphate, tricalciumphosphate, calcium polymetaphosphate, insoluble sodiumpolymetaphosphate, hydrated alumina, and resinous abrasive materialssuch as particulate condensation products of urea and formaldehyde, andothers such as disclosed by Cooley et al. in U.S. Pat. No. 3,070,510,Dec. 25, 1962, incorporated herein by reference. Mixtures of abrasivesmay also be used.

Silica dental abrasives, of various types, can provide the uniquebenefits of exceptional dental cleaning and polishing performancewithout unduly abrading tooth enamel or dentin. Silica abrasivematerials are also exceptionally compatible with sources of solublefluoride. For these reasons they are preferred for use herein. Of coursethe abrasive selected should also exhibit excellent compatibility withsoluble strontium ion sources.

The silica abrasive polishing materials useful herein, as well as theother abrasives, generally have an average particle size ranging betweenabout 0.1 to 30 microns, preferably 5 and 15 microns. The silicaabrasive can be precipitated silica or silica gels such as the silicaxerogels described in Pader et al., U.S. Pat. No. 3,538,230, issued Mar.2, 1970 and DiGiulio, U.S. Pat. No. 3,862,307, June 21, 1975, bothincorporated herein by reference. Preferred are the silica xerogelsmarketed under the tradename "Syloid" by the W.R. Grace & Company,Davison Chemical Division. Preferred precipitated silica materialsinclude those marketed by the J.M. Huber Corporation under thetradename, "Zeodent", particularly the silica carrying the designation"Zeodent 119". These silica abrasive are described in U.S. Patent4,340,583, July 29, 1982, incorporated herein by reference.

The abrasive in the dentifrice compositions described herein is presentat a level of from about 6% to about 70%, preferably from about 15% toabout 25% when the dentifrice is a toothpaste. Higher levels, as high as90%, may be used if the composition is a toothpowder.

Flavoring agents can also be added to the dentifrice and othercompositions of the present invention. Suitable flavoring gents includeoil of wintergreen, oil of peppermint, oil of spearmint, oil ofsassafras, and oil of clove. Sweetening agents are also useful andinclude aspartame, acesulfame, saccharin, dextrose, levulose and sodiumcyclamate. Flavoring and sweetening agents are generally used in thecompositions herein at levels of from about 0.005% to about 2% byweight.

The compositions of this invention also contain emulsifying agents.Suitable emulsifying agents are those which are reasonably stable andfoam throughout a wide pH range, including non-soap anionic, nonionic,cationic, zwitterionic and amphoteric organic synthetic detergents. Manyof these suitable surfactants are disclosed by Gieske et al. in U.S.Pat. No. 4,051,234, Sept. 27, 1977 incorporated herein by reference.

Water is also present in the compositions of this invention. Wateremployed in the preparation of commercially suitable compositions shouldpreferably be deionized and free of organic impurities. Water generallycomprises from about 10% to 50%, preferably from about 20% to 40%, byweight of the toothpaste compositions herein. These amounts of waterinclude the free water which is added plus that which is introduced withother materials such as with sorbitol.

In preparing toothpastes, it is necessary to add some thickeningmaterial to provide a desirable consistency. Preferred thickening agentsare carboxyvinyl polymers, carrageenan, hydroxyethyl cellulose and watersoluble salts of cellulose ethers such as sodium carboxymethyl celluloseand sodium carboxymethyl hydroxyethyl cellulose. Natural gums such asgum karaya, gum arabic, and gum tragacanth and polysaccharide gums suchas xanthan gum can also be used. Colloidal magnesium aluminum silicateor finely divided silica can be used as part of the thickening agent tofurther improve texture. Thickening agents in an amount from 0.5% to5.0% by weight of the total composition may be used.

It is also desirable to include a humectant in a toothpaste to keep itfrom hardening. Suitable humectants include glycerin, sorbitol, andother edible polyhydric alcohols at a level of from about 10% to about70%.

Another preferred embodiment of the present invention is a mouthwashcomposition. Conventional mouthwash composition components can comprisethe carrier for the actives of the present invention. Mouthwashesgenerally comprise from about 20:1 to about 2:1 of a water/ethyl alcoholsolution and preferably other ingredients such as flavor, sweeteners,humectants and sudsing agents such as those described above. Thehumectants, such as glycerin and sorbitol give a moist feel to themouth. Generally, on a weight basis the mouthwashes of the inventioncomprise 5% to 60% (preferably 10% to 25%) ethyl alcohol, 0% to 20%(preferably 5% to 20%) of a humectant, 0% to 2% (preferably 0.01% to0.15%) emulsifying agent, 0% to 0.5% (preferably 0.005% to 0.06%)sweetening agent such as saccharin, 0% to 0.3% (preferably from 0.03% to0.3%) flavoring agent, and the balance water.

Suitable lozenge and chewing gum components are disclosed in U.S. Pat.No. 4,083,955, Apr. 11, 1978 to Grabenstetter et al., incorporatedherein by reference.

Suitable topical dental gels generally comprise a base of a humectantsuch as glycerine thickened with a suitable agent. Such gels generallydo not contain an abrasive.

The pH of the present compositions and/or its pH in the mouth can be anypH which is safe for the mouth's hard and soft tissues. Such pH's aregenerally from about 3 to about 10, preferably from about 4 to about 8.The present compositions, since they are designed to deliver fluoride totooth enamel; should not contain materials which would cause significantloss of strotinum and/or fluoride ions.

METHOD OF MANUFACTURE

The carrier compositions of the present invention can be made usingmethods which are common in the oral products area. However thestrontium ion source and the polyacrylic acid polymer should be addedprior to the addition of the fluoride ion source. This is to ensure thatstrontium and fluoride do not form an insoluble precipitate. A specificmethod of manufacture is set forth in the Examples.

COMPOSITION USE

The present invention in its method aspect involves applying to the oralcavity safe and effective amounts of the compositions described herein.These amounts (e.g. from about 0.3 to about 15g), if it is a toothpasteor mouthwash, are kept in the mouth for from about 15 to about 30seconds.

The following examples further describe and demonstrate preferredembodiments within the scope of the present invention. The examples aregiven solely for illustration and are not to be construed as limitationsof this invention as many variations thereof are possible withoutdeparting from the spirit and scope thereof.

EXAMPLE I

The composition given below is exemplary of the present invention.

    ______________________________________                                        Component            Weight %                                                 ______________________________________                                        Sodium Fluoride      0.243                                                    Strontium Chloride 6H.sub.2 O                                                                      0.667                                                    Silica Dental Abrasive.sup.1                                                                       20.000                                                   Polyacrylic Acid.sup.2                                                                             0.280                                                    Sodium Saccharin     0.130                                                    Titanium Dioxide     0.700                                                    Flavor               0.600                                                    Carboxymethylcellulose                                                                             0.600                                                    Surfactant-Tween 80.sup.3                                                                          0.900                                                    Polyethyleneglycol MW 600                                                                          5.000                                                    Triethanolamine      1.000                                                    Dye                  0.050                                                    Water                19.000                                                   Sorbitol (70% Aqueous Solution)                                                                    q.s. 100%                                                ______________________________________                                         .sup.1 Precipitated silica abrasive offered by J. M. Huber Company as         Zeodent119                                                                    .sup.2 Polyacrylic acid polymer having mass average molecular weight of       about 4500 offered by Rohm and Haas                                           .sup.3 POE (20) sorbitan monooleate offered by ICI Americas Inc.         

The above composition is prepared by putting 50% of the sorbitol into amain mix tank, adding all of the polyacrylic acid and 50% of the waterand mixing for a few minutes. Strontium chloride is then dissolved in10% of the water and added to the main mix tank with the desired pHbeing obtained by immediately adding HCl or NaOH. Next sodium fluorideis dissolved in the remaining water and added to the main mix tank,followed by the silica abrasive, sodium saccharin, titanium dioxide andflavor. In a separate tank, the binder is mixed with the remainingsorbitol and added to the main mix tank followed by the surfactant andthe dye. The final mixture is heated to 70° C., processed through a milland deaerated if necessary.

EXAMPLE II

Given below is another example of the present invention.

    ______________________________________                                        Component            Weight %                                                 ______________________________________                                        Sodium Fluoride      0.111                                                    Strontium Chloride 6H.sub.2 O                                                                      0.333                                                    Silica Dental Abrasive.sup.1                                                                       20.000                                                   Polyacrylic Acid.sup.2                                                                             0.500                                                    Sodium Saccharin     0.130                                                    Titanium Dioxide     0.100                                                    Flavor               0.600                                                    Carboxymethylcellulose                                                                             0.600                                                    Sodium Alkyl Sulfate 2.500                                                    Dye                  0.050                                                    Water                19.000                                                   Sorbitol (70% Aqueous Solution)                                                                    q.s. 100%                                                ______________________________________                                         .sup.1 Precipitated silica abrasive offered by J. M. Huber Company as         Zeodent119                                                                    .sup.2 Polyacrylic acid polymer having mass average molecuar weight of        about 4500 offered by Rohm and Haas                                      

EXAMPLE III

Given below is yet another example of the present invention.

    ______________________________________                                        Component            Weight %                                                 ______________________________________                                        Sodium Flouride      0.243                                                    Strontium Chloride 6H.sub.2 O                                                                      0.100                                                    Silica Dental Abrasive.sup.1                                                                       20.000                                                   Polyacrylic Acid.sup.2                                                                             2.000                                                    Sodium Saccharin     0.130                                                    Titanium Dioxide     0.700                                                    Flavor               0.600                                                    Carboxymethylcellulose                                                                             0.600                                                    Sodium Lauroyl Sarcosinate                                                                         1.500                                                    Dye                  0.050                                                    Water                19.000                                                   Sorbitol (70% Aqueous Solution)                                                                    q.s. 100%                                                ______________________________________                                         .sup.1 Precipitated silica abrasive offered by J. M. Huber Company as         Zeodent119                                                                    .sup.2 Polyacrylic acid polymer having mass average molecular weight of       about 4500 offered by Rohm and Haas                                      

EXAMPLE IV

Given below is another composition representative of the presentinvention.

    ______________________________________                                        Component            Weight %                                                 ______________________________________                                        Sodium Flouride      0.443                                                    Strontium Chloride 6H.sub.2 O                                                                      1.200                                                    Silica Dental Abrasive.sup.1                                                                       20.000                                                   Polyacrylic Acid.sup.2                                                                             3.000                                                    Sodium Saccharin     0.130                                                    Titanium Dioxide     0.100                                                    Flavor               0.600                                                    Carboxymethylcellulose                                                                             0.600                                                    Cocoyl Isethionate   2.000                                                    Dye                  0.050                                                    Water                19.000                                                   Sorbitol (70% Aqueous Solution)                                                                    q.s. 100%                                                ______________________________________                                         .sup.1 Precipitated silica abrasive offered by J. M. Huber Company as         Zeodent119                                                                    .sup.2 Polyacrylic acid polymer having mass average molecular weight of       about 4500 offered by Rohm and Haas                                      

All of the above compositions provide improved fluoride uptake by dentalenamel. Similar performance is obtained if the polyacrylic acid isreplaced by another acrylic acid polymer or copolymer having a molecularweight of from about 1000 to about 1,200,000. Similarly strontiumchloride may be replaced with another strontium salt such as strontiumacetate, strontium lactate, strontium salicylate, strontium hydroxide orstrontium glyconate.

FLUORIDE UPTAKE ANALYSIS

The ability of compositions of the present invention to deliver enhancedfluoride to dental enamel was measured using an in-vitro enamel discmethod.

Enamel discs (4mm diameter) were mounted in lucite rods, then ground andpolished--removing at least 40um of the enamel surface. Discs weredecalcified for 46 hours at 37° C. in 8ml of 0.1M lactic acid plus1.0×10⁻⁴ M disodium-methane-hydroxydiphosphonate (MHDP) adjusted to pH4.5. The depth of demineralization was approximately 100um. The discwere placed in groups of four (4) per treatment group.

At the beginning of the study, each treatment group was suspended forone (1) hour in 15 grams of fresh, paraffin stimulated, pooled humansaliva under constant agitation. The treatment groups were then exposedto 20ml of an appropriate test solution for one (1) minute, followed bya thorough rinsing in deionized water. The one minute treatment wasfollowed by one (1) hour soaking in the saliva baths. This cyclicpattern (one minute treatment/thorough rinse/one hour saliva soak) wasrepeated seven (7) times a day for four (4) days for a total oftwenty-eight (28) treatments. Saliva baths were changed twice daily tomaintain their freshness. At the end of each day, the discs werethoroughly rinsed with deionized water and placed upright in a moistatmosphere under refrigeration in order to minimize any microbialgrowth.

Following the 28th treatment, specimens were thoroughly rinsed withdeionized water and analyzed for fluoride content using a microdrillbiopsy technique. In this technique, a carbide dental bar (diameterapproximately 0.45mm) penetrates the surface of the discs and travels tothe base of the demineralized area, in this case 100 um. The displacedenamel powder is recovered into a small polyethylene vial, where it isdissolved with 20ul of 0.5M HCIO₄. To this is added 40ul of deionizedwater, then 40ul of a Citrate-EDTA buffer resulting in a total volume of100ul for analysis. Fluoride analysis of this solution is done using anOrion Fluoride Ion-specific electrode (Model 96-09-00) that has beenappropriately calibrated for the range of these analytical samples.

Statistical analyses were done using a standard t- test forsignificance.

Using the above described procedure, various strontium ionconcentrations and polyacrylic acid polymer levels were used with 1100ppm F⁻ on to determine the amount of F⁻ taken up by the enamel.

    ______________________________________                                        Treatment Solutions*                                                                             %                                                                             Polycarylic                                                                   Acid                                                       F.sup.- (ppm)                                                                         SR.sup.++ (ppm)                                                                          MW 4500    F.sup.- Uptake (μg/cm.sup.2)                 ______________________________________                                         1100 1100 1100 1100 1100 1100 1100 1100                                               4400 2200 1100 500 50 100 10 --                                                          6.0 3.0 1.5 0.680 .068 .136 .014 --                                                      ##STR3##                                       ______________________________________                                         *Actual levels in test solutions were at 1/4 these levels. These numbers      represent the equivalents in whole dentifrice before dilution.           

The numbers within the brackets are different from those outside at the95% cofidence level.

What is claimed is:
 1. An oral composition in the form of a toothpaste,mouthwash, topical dental gel, lozenge or chewing gum comprising:(a) asafe and effective amount of a polymer selected from the groupconsisting of polyacrylic acid polymers, copolymers of acrylic acid andmixtures thereof; (b) a safe and effective amount of a soluble strontiumion source; (c) a safe and effective amount of a soluble fluoride ionsource; and (d) a pharmaceutically acceptable carrier.
 2. An oralcomposition according to claim 1 wherein (a) is a copolymer of acrylicacid and a monomer selected from the group consisting of methacrylicacid, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate,3-hydroxypropyl methacrylate, acrylamide and mixtures thereof.
 3. Anoral composition according to claim 1 wherein (a) is a polyacrylic acidpolymer and is present at a level of from about 0.0003% to about 13%. 4.An oral composition according to claim 3 wherein the pharmaceuticallyacceptable carrier is a toothpaste.
 5. An oral composition according toclaim 4 wherein the soluble strontium ion source is present at a levelof from about 2 to about 10,000 ppm Sr⁺⁺ in the composition.
 6. An oralcomposition according to claim 5 wherein the polyacrylic acid polymerhas a molecular weight of from about 1000 to about 1,200,000.
 7. An oralcomposition according to claim 6 which also contains a silica dentalabrasive.
 8. An oral composition according to claim 7 wherein thesoluble fluoride ion source is sodium fluoride present at a levelsufficient to give from about 25 to about 5000 ppm F⁻ in thecomposition.
 9. An oral composition according to claim 1 wherein thepharmaceutically acceptable carrier is a mouthwash.
 10. An oralcomposition according to claim 1 wherein the pharmaceutically acceptablecarrier is a topical dental gel.
 11. An oral composition according toclaim 9 wherein (a) is a polyacrylic acid polymer and is present at alevel of from about 0.001% to about 13%.
 12. An oral compositionaccording to claim 11 wherein the soluble strontium ion source ispresent at a level of from about 2 to about 10,000 ppm in thecomposition.
 13. An oral composition according to claim 12 wherein thesoluble fluoride ion source is sodium fluoride present at a levelsufficient to give from about 25 to about 5000 ppm F⁻ in thecomposition.
 14. An oral composition according to claim 1 wherein thepharmaceutically acceptable carrier is a lozenge.
 15. An oralcomposition according to claim 1 wherein the pharmaceutically acceptablecarrier is a chewing gum.
 16. A method of applying fluoride to toothenamel/dentin comprising applying a safe and effective amount of thecomposition according to claim 1 to the enamel/dentin.
 17. A methodaccording to claim 16 wherein the composition is according to claim 4.18. A method according to claim 16 wherein the composition is accordingto claim
 8. 19. A method according to claim 16 wherein the compositionis according to claim
 9. 20. A method according to claim 16 wherein thecomposition is according to claim 10.